1/*
2 * Copyright 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_GUI_BUFFERQUEUEPRODUCER_H
18#define ANDROID_GUI_BUFFERQUEUEPRODUCER_H
19
20#include <gui/BufferQueueDefs.h>
21#include <gui/IGraphicBufferProducer.h>
22
23namespace android {
24
25class BufferSlot;
26
27class BufferQueueProducer : public BnGraphicBufferProducer,
28                            private IBinder::DeathRecipient {
29public:
30    friend class BufferQueue; // Needed to access binderDied
31
32    BufferQueueProducer(const sp<BufferQueueCore>& core);
33    virtual ~BufferQueueProducer();
34
35    // requestBuffer returns the GraphicBuffer for slot N.
36    //
37    // In normal operation, this is called the first time slot N is returned
38    // by dequeueBuffer.  It must be called again if dequeueBuffer returns
39    // flags indicating that previously-returned buffers are no longer valid.
40    virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);
41
42    // see IGraphicsBufferProducer::setMaxDequeuedBufferCount
43    virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
44
45    // see IGraphicsBufferProducer::setAsyncMode
46    virtual status_t setAsyncMode(bool async);
47
48    // dequeueBuffer gets the next buffer slot index for the producer to use.
49    // If a buffer slot is available then that slot index is written to the
50    // location pointed to by the buf argument and a status of OK is returned.
51    // If no slot is available then a status of -EBUSY is returned and buf is
52    // unmodified.
53    //
54    // The outFence parameter will be updated to hold the fence associated with
55    // the buffer. The contents of the buffer must not be overwritten until the
56    // fence signals. If the fence is Fence::NO_FENCE, the buffer may be
57    // written immediately.
58    //
59    // The width and height parameters must be no greater than the minimum of
60    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
61    // An error due to invalid dimensions might not be reported until
62    // updateTexImage() is called.  If width and height are both zero, the
63    // default values specified by setDefaultBufferSize() are used instead.
64    //
65    // If the format is 0, the default format will be used.
66    //
67    // The usage argument specifies gralloc buffer usage flags.  The values
68    // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER.  These
69    // will be merged with the usage flags specified by setConsumerUsageBits.
70    //
71    // The return value may be a negative error value or a non-negative
72    // collection of flags.  If the flags are set, the return values are
73    // valid, but additional actions must be performed.
74    //
75    // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the
76    // producer must discard cached GraphicBuffer references for the slot
77    // returned in buf.
78    // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer
79    // must discard cached GraphicBuffer references for all slots.
80    //
81    // In both cases, the producer will need to call requestBuffer to get a
82    // GraphicBuffer handle for the returned slot.
83    virtual status_t dequeueBuffer(int *outSlot, sp<Fence>* outFence,
84            uint32_t width, uint32_t height, PixelFormat format,
85            uint32_t usage);
86
87    // See IGraphicBufferProducer::detachBuffer
88    virtual status_t detachBuffer(int slot);
89
90    // See IGraphicBufferProducer::detachNextBuffer
91    virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
92            sp<Fence>* outFence);
93
94    // See IGraphicBufferProducer::attachBuffer
95    virtual status_t attachBuffer(int* outSlot, const sp<GraphicBuffer>& buffer);
96
97    // queueBuffer returns a filled buffer to the BufferQueue.
98    //
99    // Additional data is provided in the QueueBufferInput struct.  Notably,
100    // a timestamp must be provided for the buffer. The timestamp is in
101    // nanoseconds, and must be monotonically increasing. Its other semantics
102    // (zero point, etc) are producer-specific and should be documented by the
103    // producer.
104    //
105    // The caller may provide a fence that signals when all rendering
106    // operations have completed.  Alternatively, NO_FENCE may be used,
107    // indicating that the buffer is ready immediately.
108    //
109    // Some values are returned in the output struct: the current settings
110    // for default width and height, the current transform hint, and the
111    // number of queued buffers.
112    virtual status_t queueBuffer(int slot,
113            const QueueBufferInput& input, QueueBufferOutput* output);
114
115    // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
116    // queue it for use by the consumer.
117    //
118    // The buffer will not be overwritten until the fence signals.  The fence
119    // will usually be the one obtained from dequeueBuffer.
120    virtual status_t cancelBuffer(int slot, const sp<Fence>& fence);
121
122    // Query native window attributes.  The "what" values are enumerated in
123    // window.h (e.g. NATIVE_WINDOW_FORMAT).
124    virtual int query(int what, int* outValue);
125
126    // connect attempts to connect a producer API to the BufferQueue.  This
127    // must be called before any other IGraphicBufferProducer methods are
128    // called except for getAllocator.  A consumer must already be connected.
129    //
130    // This method will fail if connect was previously called on the
131    // BufferQueue and no corresponding disconnect call was made (i.e. if
132    // it's still connected to a producer).
133    //
134    // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
135    virtual status_t connect(const sp<IProducerListener>& listener,
136            int api, bool producerControlledByApp, QueueBufferOutput* output);
137
138    // disconnect attempts to disconnect a producer API from the BufferQueue.
139    // Calling this method will cause any subsequent calls to other
140    // IGraphicBufferProducer methods to fail except for getAllocator and connect.
141    // Successfully calling connect after this will allow the other methods to
142    // succeed again.
143    //
144    // This method will fail if the the BufferQueue is not currently
145    // connected to the specified producer API.
146    virtual status_t disconnect(int api);
147
148    // Attaches a sideband buffer stream to the IGraphicBufferProducer.
149    //
150    // A sideband stream is a device-specific mechanism for passing buffers
151    // from the producer to the consumer without using dequeueBuffer/
152    // queueBuffer. If a sideband stream is present, the consumer can choose
153    // whether to acquire buffers from the sideband stream or from the queued
154    // buffers.
155    //
156    // Passing NULL or a different stream handle will detach the previous
157    // handle if any.
158    virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
159
160    // See IGraphicBufferProducer::allocateBuffers
161    virtual void allocateBuffers(uint32_t width, uint32_t height,
162            PixelFormat format, uint32_t usage);
163
164    // See IGraphicBufferProducer::allowAllocation
165    virtual status_t allowAllocation(bool allow);
166
167    // See IGraphicBufferProducer::setGenerationNumber
168    virtual status_t setGenerationNumber(uint32_t generationNumber);
169
170    // See IGraphicBufferProducer::getConsumerName
171    virtual String8 getConsumerName() const override;
172
173    // See IGraphicBufferProducer::getNextFrameNumber
174    virtual uint64_t getNextFrameNumber() const override;
175
176    // See IGraphicBufferProducer::setSharedBufferMode
177    virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
178
179    // See IGraphicBufferProducer::setAutoRefresh
180    virtual status_t setAutoRefresh(bool autoRefresh) override;
181
182    // See IGraphicBufferProducer::setDequeueTimeout
183    virtual status_t setDequeueTimeout(nsecs_t timeout) override;
184
185    // See IGraphicBufferProducer::getLastQueuedBuffer
186    virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
187            sp<Fence>* outFence, float outTransformMatrix[16]) override;
188
189    // See IGraphicBufferProducer::getUniqueId
190    virtual status_t getUniqueId(uint64_t* outId) const override;
191
192private:
193    // This is required by the IBinder::DeathRecipient interface
194    virtual void binderDied(const wp<IBinder>& who);
195
196    // Returns the slot of the next free buffer if one is available or
197    // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
198    int getFreeBufferLocked() const;
199
200    // Returns the next free slot if one is available or
201    // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
202    int getFreeSlotLocked() const;
203
204    // waitForFreeSlotThenRelock finds the oldest slot in the FREE state. It may
205    // block if there are no available slots and we are not in non-blocking
206    // mode (producer and consumer controlled by the application). If it blocks,
207    // it will release mCore->mMutex while blocked so that other operations on
208    // the BufferQueue may succeed.
209    enum class FreeSlotCaller {
210        Dequeue,
211        Attach,
212    };
213    status_t waitForFreeSlotThenRelock(FreeSlotCaller caller, int* found) const;
214
215    sp<BufferQueueCore> mCore;
216
217    // This references mCore->mSlots. Lock mCore->mMutex while accessing.
218    BufferQueueDefs::SlotsType& mSlots;
219
220    // This is a cached copy of the name stored in the BufferQueueCore.
221    // It's updated during connect and dequeueBuffer (which should catch
222    // most updates).
223    String8 mConsumerName;
224
225    uint32_t mStickyTransform;
226
227    // This saves the fence from the last queueBuffer, such that the
228    // next queueBuffer call can throttle buffer production. The prior
229    // queueBuffer's fence is not nessessarily available elsewhere,
230    // since the previous buffer might have already been acquired.
231    sp<Fence> mLastQueueBufferFence;
232
233    Rect mLastQueuedCrop;
234    uint32_t mLastQueuedTransform;
235
236    // Take-a-ticket system for ensuring that onFrame* callbacks are called in
237    // the order that frames are queued. While the BufferQueue lock
238    // (mCore->mMutex) is held, a ticket is retained by the producer. After
239    // dropping the BufferQueue lock, the producer must wait on the condition
240    // variable until the current callback ticket matches its retained ticket.
241    Mutex mCallbackMutex;
242    int mNextCallbackTicket; // Protected by mCore->mMutex
243    int mCurrentCallbackTicket; // Protected by mCallbackMutex
244    Condition mCallbackCondition;
245
246    // Sets how long dequeueBuffer or attachBuffer will block if a buffer or
247    // slot is not yet available.
248    nsecs_t mDequeueTimeout;
249
250}; // class BufferQueueProducer
251
252} // namespace android
253
254#endif
255